The present invention relates generally to moisture sensors and, specifically to, time domain reflectometry moisture sensors.
The use of time domain reflectometry has been previously known as a method for determining the level of liquids in tanks and other enclosures. Furthermore, time domain reflectometry sensors are used to measure moisture in various media via high velocity wave propagation. The velocity of the wave propagation in a time domain reflectometry sensor is on the order of one nano-second per foot. In order to process the wave propagation at such velocity, high speed electronics are required in a wave detector circuit. Another approach to processing the wave propagation through a media involves high speed retriggering excitation wave pulses upon detection of the reflected wave pulse resulting in a continuous oscillator function where the frequency represents the state of the media being measured.
The problems with the above approaches are that high speed electronics increase the product cost of the time domain reflectometry moisture sensor and a continuous frequency of an oscillator function needs to be divided into measurable parameter. Accordingly, there is a need in the art for a time domain reflectometry functioning as a liquid sensor that does not require high speed electronics in the wave detector.